1. Field of the Invention
The present invention relates to an illuminating arrangement for a field-effect liquid-crystal display with a transparent, light-distributing plate of homogeneous constitution applied to the back of the liquid-crystal display.
2. Description of the Prior Art
Field-effect liquid-crystal displays with side-illuminating arrangements for light entry parallel to the plate surfaces of the liquid-crystal cell or at the edge of the narrow side of the liquid-crystal cell are already known in various configurations and styles as, for example, in DT-OS No. 2,310,219 and in Electronic Design 14, July 5, 1974 and 16, Aug. 2, 1974. Such accessory, external light sources are indispensable for readability in the dark.
In the current commercial models, however, the luminosity is poor to unsatisfactory coupling of the light rays to the medium to be illuminated. Distribution of light intensity over the entire plate surface is also nonuniform and is generally insufficient for enabling reading in the dark.